drivers/base/cacheinfo.c

   1 /*
   2  * cacheinfo support - processor cache information via sysfs
   3  *
   4  * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
   5  * Author: Sudeep Holla <sudeep.holla@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  12  * kind, whether express or implied; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include <linux/bitops.h>
  20 #include <linux/cacheinfo.h>
  21 #include <linux/compiler.h>
  22 #include <linux/cpu.h>
  23 #include <linux/device.h>
  24 #include <linux/init.h>
  25 #include <linux/of.h>
  26 #include <linux/sched.h>
  27 #include <linux/slab.h>
  28 #include <linux/smp.h>
  29 #include <linux/sysfs.h>
  30
  31 /* pointer to per cpu cacheinfo */
  32 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
  33 #define ci_cacheinfo(cpu)       (&per_cpu(ci_cpu_cacheinfo, cpu))
  34 #define cache_leaves(cpu)       (ci_cacheinfo(cpu)->num_leaves)
  35 #define per_cpu_cacheinfo(cpu)  (ci_cacheinfo(cpu)->info_list)
  36
  37 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
  38 {
  39         return ci_cacheinfo(cpu);
  40 }
  41
  42 #ifdef CONFIG_OF
  43 static int cache_setup_of_node(unsigned int cpu)
  44 {
  45         struct device_node *np;
  46         struct cacheinfo *this_leaf;
  47         struct device *cpu_dev = get_cpu_device(cpu);
  48         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
  49         unsigned int index = 0;
  50
  51         /* skip if of_node is already populated */
  52         if (this_cpu_ci->info_list->of_node)
  53                 return 0;
  54
  55         if (!cpu_dev) {
  56                 pr_err("No cpu device for CPU %d\n", cpu);
  57                 return -ENODEV;
  58         }
  59         np = cpu_dev->of_node;
  60         if (!np) {
  61                 pr_err("Failed to find cpu%d device node\n", cpu);
  62                 return -ENOENT;
  63         }
  64
  65         while (index < cache_leaves(cpu)) {
  66                 this_leaf = this_cpu_ci->info_list + index;
  67                 if (this_leaf->level != 1)
  68                         np = of_find_next_cache_node(np);
  69                 else
  70                         np = of_node_get(np);/* cpu node itself */
  71                 if (!np)
  72                         break;
  73                 this_leaf->of_node = np;
  74                 index++;
  75         }
  76
  77         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
  78                 return -ENOENT;
  79
  80         return 0;
  81 }
  82
  83 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  84                                            struct cacheinfo *sib_leaf)
  85 {
  86         return sib_leaf->of_node == this_leaf->of_node;
  87 }
  88 #else
  89 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
  90 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  91                                            struct cacheinfo *sib_leaf)
  92 {
  93         /*
  94          * For non-DT systems, assume unique level 1 cache, system-wide
  95          * shared caches for all other levels. This will be used only if
  96          * arch specific code has not populated shared_cpu_map
  97          */
  98         return !(this_leaf->level == 1);
  99 }
 100 #endif
 101
 102 static int cache_shared_cpu_map_setup(unsigned int cpu)
 103 {
 104         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 105         struct cacheinfo *this_leaf, *sib_leaf;
 106         unsigned int index;
 107         int ret;
 108
 109         ret = cache_setup_of_node(cpu);
 110         if (ret)
 111                 return ret;
 112
 113         for (index = 0; index < cache_leaves(cpu); index++) {
 114                 unsigned int i;
 115
 116                 this_leaf = this_cpu_ci->info_list + index;
 117                 /* skip if shared_cpu_map is already populated */
 118                 if (!cpumask_empty(&this_leaf->shared_cpu_map))
 119                         continue;
 120
 121                 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
 122                 for_each_online_cpu(i) {
 123                         struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
 124
 125                         if (i == cpu || !sib_cpu_ci->info_list)
 126                                 continue;/* skip if itself or no cacheinfo */
 127                         sib_leaf = sib_cpu_ci->info_list + index;
 128                         if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 129                                 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
 130                                 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
 131                         }
 132                 }
 133         }
 134
 135         return 0;
 136 }
 137
 138 static void cache_shared_cpu_map_remove(unsigned int cpu)
 139 {
 140         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 141         struct cacheinfo *this_leaf, *sib_leaf;
 142         unsigned int sibling, index;
 143
 144         for (index = 0; index < cache_leaves(cpu); index++) {
 145                 this_leaf = this_cpu_ci->info_list + index;
 146                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 147                         struct cpu_cacheinfo *sib_cpu_ci;
 148
 149                         if (sibling == cpu) /* skip itself */
 150                                 continue;
 151
 152                         sib_cpu_ci = get_cpu_cacheinfo(sibling);
 153                         if (!sib_cpu_ci->info_list)
 154                                 continue;
 155
 156                         sib_leaf = sib_cpu_ci->info_list + index;
 157                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 158                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 159                 }
 160                 of_node_put(this_leaf->of_node);
 161         }
 162 }
 163
 164 static void free_cache_attributes(unsigned int cpu)
 165 {
 166         if (!per_cpu_cacheinfo(cpu))
 167                 return;
 168
 169         cache_shared_cpu_map_remove(cpu);
 170
 171         kfree(per_cpu_cacheinfo(cpu));
 172         per_cpu_cacheinfo(cpu) = NULL;
 173 }
 174
 175 int __weak init_cache_level(unsigned int cpu)
 176 {
 177         return -ENOENT;
 178 }
 179
 180 int __weak populate_cache_leaves(unsigned int cpu)
 181 {
 182         return -ENOENT;
 183 }
 184
 185 static int detect_cache_attributes(unsigned int cpu)
 186 {
 187         int ret;
 188
 189         if (init_cache_level(cpu) || !cache_leaves(cpu))
 190                 return -ENOENT;
 191
 192         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 193                                          sizeof(struct cacheinfo), GFP_KERNEL);
 194         if (per_cpu_cacheinfo(cpu) == NULL)
 195                 return -ENOMEM;
 196
 197         ret = populate_cache_leaves(cpu);
 198         if (ret)
 199                 goto free_ci;
 200         /*
 201          * For systems using DT for cache hierarchy, of_node and shared_cpu_map
 202          * will be set up here only if they are not populated already
 203          */
 204         ret = cache_shared_cpu_map_setup(cpu);
 205         if (ret) {
 206                 pr_warn("Unable to detect cache hierarchy from DT for CPU %d\n",
 207                         cpu);
 208                 goto free_ci;
 209         }
 210         return 0;
 211
 212 free_ci:
 213         free_cache_attributes(cpu);
 214         return ret;
 215 }
 216
 217 /* pointer to cpuX/cache device */
 218 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 219 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 220
 221 static cpumask_t cache_dev_map;
 222
 223 /* pointer to array of devices for cpuX/cache/indexY */
 224 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 225 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 226 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 227
 228 #define show_one(file_name, object)                             \
 229 static ssize_t file_name##_show(struct device *dev,             \
 230                 struct device_attribute *attr, char *buf)       \
 231 {                                                               \
 232         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 233         return sprintf(buf, "%u\n", this_leaf->object);         \
 234 }
 235
 236 show_one(level, level);
 237 show_one(coherency_line_size, coherency_line_size);
 238 show_one(number_of_sets, number_of_sets);
 239 show_one(physical_line_partition, physical_line_partition);
 240 show_one(ways_of_associativity, ways_of_associativity);
 241
 242 static ssize_t size_show(struct device *dev,
 243                          struct device_attribute *attr, char *buf)
 244 {
 245         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 246
 247         return sprintf(buf, "%uK\n", this_leaf->size >> 10);
 248 }
 249
 250 static ssize_t shared_cpumap_show_func(struct device *dev, bool list, char *buf)
 251 {
 252         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 253         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 254
 255         return cpumap_print_to_pagebuf(list, buf, mask);
 256 }
 257
 258 static ssize_t shared_cpu_map_show(struct device *dev,
 259                                    struct device_attribute *attr, char *buf)
 260 {
 261         return shared_cpumap_show_func(dev, false, buf);
 262 }
 263
 264 static ssize_t shared_cpu_list_show(struct device *dev,
 265                                     struct device_attribute *attr, char *buf)
 266 {
 267         return shared_cpumap_show_func(dev, true, buf);
 268 }
 269
 270 static ssize_t type_show(struct device *dev,
 271                          struct device_attribute *attr, char *buf)
 272 {
 273         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 274
 275         switch (this_leaf->type) {
 276         case CACHE_TYPE_DATA:
 277                 return sprintf(buf, "Data\n");
 278         case CACHE_TYPE_INST:
 279                 return sprintf(buf, "Instruction\n");
 280         case CACHE_TYPE_UNIFIED:
 281                 return sprintf(buf, "Unified\n");
 282         default:
 283                 return -EINVAL;
 284         }
 285 }
 286
 287 static ssize_t allocation_policy_show(struct device *dev,
 288                                       struct device_attribute *attr, char *buf)
 289 {
 290         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 291         unsigned int ci_attr = this_leaf->attributes;
 292         int n = 0;
 293
 294         if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
 295                 n = sprintf(buf, "ReadWriteAllocate\n");
 296         else if (ci_attr & CACHE_READ_ALLOCATE)
 297                 n = sprintf(buf, "ReadAllocate\n");
 298         else if (ci_attr & CACHE_WRITE_ALLOCATE)
 299                 n = sprintf(buf, "WriteAllocate\n");
 300         return n;
 301 }
 302
 303 static ssize_t write_policy_show(struct device *dev,
 304                                  struct device_attribute *attr, char *buf)
 305 {
 306         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 307         unsigned int ci_attr = this_leaf->attributes;
 308         int n = 0;
 309
 310         if (ci_attr & CACHE_WRITE_THROUGH)
 311                 n = sprintf(buf, "WriteThrough\n");
 312         else if (ci_attr & CACHE_WRITE_BACK)
 313                 n = sprintf(buf, "WriteBack\n");
 314         return n;
 315 }
 316
 317 static DEVICE_ATTR_RO(level);
 318 static DEVICE_ATTR_RO(type);
 319 static DEVICE_ATTR_RO(coherency_line_size);
 320 static DEVICE_ATTR_RO(ways_of_associativity);
 321 static DEVICE_ATTR_RO(number_of_sets);
 322 static DEVICE_ATTR_RO(size);
 323 static DEVICE_ATTR_RO(allocation_policy);
 324 static DEVICE_ATTR_RO(write_policy);
 325 static DEVICE_ATTR_RO(shared_cpu_map);
 326 static DEVICE_ATTR_RO(shared_cpu_list);
 327 static DEVICE_ATTR_RO(physical_line_partition);
 328
 329 static struct attribute *cache_default_attrs[] = {
 330         &dev_attr_type.attr,
 331         &dev_attr_level.attr,
 332         &dev_attr_shared_cpu_map.attr,
 333         &dev_attr_shared_cpu_list.attr,
 334         &dev_attr_coherency_line_size.attr,
 335         &dev_attr_ways_of_associativity.attr,
 336         &dev_attr_number_of_sets.attr,
 337         &dev_attr_size.attr,
 338         &dev_attr_allocation_policy.attr,
 339         &dev_attr_write_policy.attr,
 340         &dev_attr_physical_line_partition.attr,
 341         NULL
 342 };
 343
 344 static umode_t
 345 cache_default_attrs_is_visible(struct kobject *kobj,
 346                                struct attribute *attr, int unused)
 347 {
 348         struct device *dev = kobj_to_dev(kobj);
 349         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 350         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 351         umode_t mode = attr->mode;
 352
 353         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 354                 return mode;
 355         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 356                 return mode;
 357         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 358                 return mode;
 359         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 360                 return mode;
 361         if ((attr == &dev_attr_coherency_line_size.attr) &&
 362             this_leaf->coherency_line_size)
 363                 return mode;
 364         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 365             this_leaf->size) /* allow 0 = full associativity */
 366                 return mode;
 367         if ((attr == &dev_attr_number_of_sets.attr) &&
 368             this_leaf->number_of_sets)
 369                 return mode;
 370         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 371                 return mode;
 372         if ((attr == &dev_attr_write_policy.attr) &&
 373             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 374                 return mode;
 375         if ((attr == &dev_attr_allocation_policy.attr) &&
 376             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 377                 return mode;
 378         if ((attr == &dev_attr_physical_line_partition.attr) &&
 379             this_leaf->physical_line_partition)
 380                 return mode;
 381
 382         return 0;
 383 }
 384
 385 static const struct attribute_group cache_default_group = {
 386         .attrs = cache_default_attrs,
 387         .is_visible = cache_default_attrs_is_visible,
 388 };
 389
 390 static const struct attribute_group *cache_default_groups[] = {
 391         &cache_default_group,
 392         NULL,
 393 };
 394
 395 static const struct attribute_group *cache_private_groups[] = {
 396         &cache_default_group,
 397         NULL, /* Place holder for private group */
 398         NULL,
 399 };
 400
 401 const struct attribute_group *
 402 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 403 {
 404         return NULL;
 405 }
 406
 407 static const struct attribute_group **
 408 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 409 {
 410         const struct attribute_group *priv_group =
 411                         cache_get_priv_group(this_leaf);
 412
 413         if (!priv_group)
 414                 return cache_default_groups;
 415
 416         if (!cache_private_groups[1])
 417                 cache_private_groups[1] = priv_group;
 418
 419         return cache_private_groups;
 420 }
 421
 422 /* Add/Remove cache interface for CPU device */
 423 static void cpu_cache_sysfs_exit(unsigned int cpu)
 424 {
 425         int i;
 426         struct device *ci_dev;
 427
 428         if (per_cpu_index_dev(cpu)) {
 429                 for (i = 0; i < cache_leaves(cpu); i++) {
 430                         ci_dev = per_cache_index_dev(cpu, i);
 431                         if (!ci_dev)
 432                                 continue;
 433                         device_unregister(ci_dev);
 434                 }
 435                 kfree(per_cpu_index_dev(cpu));
 436                 per_cpu_index_dev(cpu) = NULL;
 437         }
 438         device_unregister(per_cpu_cache_dev(cpu));
 439         per_cpu_cache_dev(cpu) = NULL;
 440 }
 441
 442 static int cpu_cache_sysfs_init(unsigned int cpu)
 443 {
 444         struct device *dev = get_cpu_device(cpu);
 445
 446         if (per_cpu_cacheinfo(cpu) == NULL)
 447                 return -ENOENT;
 448
 449         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 450         if (IS_ERR(per_cpu_cache_dev(cpu)))
 451                 return PTR_ERR(per_cpu_cache_dev(cpu));
 452
 453         /* Allocate all required memory */
 454         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 455                                          sizeof(struct device *), GFP_KERNEL);
 456         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 457                 goto err_out;
 458
 459         return 0;
 460
 461 err_out:
 462         cpu_cache_sysfs_exit(cpu);
 463         return -ENOMEM;
 464 }
 465
 466 static int cache_add_dev(unsigned int cpu)
 467 {
 468         unsigned int i;
 469         int rc;
 470         struct device *ci_dev, *parent;
 471         struct cacheinfo *this_leaf;
 472         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 473         const struct attribute_group **cache_groups;
 474
 475         rc = cpu_cache_sysfs_init(cpu);
 476         if (unlikely(rc < 0))
 477                 return rc;
 478
 479         parent = per_cpu_cache_dev(cpu);
 480         for (i = 0; i < cache_leaves(cpu); i++) {
 481                 this_leaf = this_cpu_ci->info_list + i;
 482                 if (this_leaf->disable_sysfs)
 483                         continue;
 484                 cache_groups = cache_get_attribute_groups(this_leaf);
 485                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 486                                            "index%1u", i);
 487                 if (IS_ERR(ci_dev)) {
 488                         rc = PTR_ERR(ci_dev);
 489                         goto err;
 490                 }
 491                 per_cache_index_dev(cpu, i) = ci_dev;
 492         }
 493         cpumask_set_cpu(cpu, &cache_dev_map);
 494
 495         return 0;
 496 err:
 497         cpu_cache_sysfs_exit(cpu);
 498         return rc;
 499 }
 500
 501 static void cache_remove_dev(unsigned int cpu)
 502 {
 503         if (!cpumask_test_cpu(cpu, &cache_dev_map))
 504                 return;
 505         cpumask_clear_cpu(cpu, &cache_dev_map);
 506
 507         cpu_cache_sysfs_exit(cpu);
 508 }
 509
 510 static int cacheinfo_cpu_callback(struct notifier_block *nfb,
 511                                   unsigned long action, void *hcpu)
 512 {
 513         unsigned int cpu = (unsigned long)hcpu;
 514         int rc = 0;
 515
 516         switch (action & ~CPU_TASKS_FROZEN) {
 517         case CPU_ONLINE:
 518                 rc = detect_cache_attributes(cpu);
 519                 if (!rc)
 520                         rc = cache_add_dev(cpu);
 521                 break;
 522         case CPU_DEAD:
 523                 cache_remove_dev(cpu);
 524                 free_cache_attributes(cpu);
 525                 break;
 526         }
 527         return notifier_from_errno(rc);
 528 }
 529
 530 static int __init cacheinfo_sysfs_init(void)
 531 {
 532         int cpu, rc = 0;
 533
 534         cpu_notifier_register_begin();
 535
 536         for_each_online_cpu(cpu) {
 537                 rc = detect_cache_attributes(cpu);
 538                 if (rc)
 539                         goto out;
 540                 rc = cache_add_dev(cpu);
 541                 if (rc) {
 542                         free_cache_attributes(cpu);
 543                         pr_err("error populating cacheinfo..cpu%d\n", cpu);
 544                         goto out;
 545                 }
 546         }
 547         __hotcpu_notifier(cacheinfo_cpu_callback, 0);
 548
 549 out:
 550         cpu_notifier_register_done();
 551         return rc;
 552 }
 553
 554 device_initcall(cacheinfo_sysfs_init);